Year	% of expense
2001	33.3366165726429
2002	35.67987774100622
2003	36.82148908029347
2004	36.42232997728193
2005	35.11293345322651
2006	34.128630705394194
2007	34.206474130851355
2008	34.9149087614857
2009	47.17481257561994
2010	47.26286474114792
2011	40.691133165119766
2012	46.780149231340076
2013	46.709919970008876
2014	46.321395871827754
2015	46.48449677897473
2016	46.74417550398054
2017	46.53406205859791
2018	46.672382137383735
2019	46.818378318096535
2020	53.189049470750994
2021	49.433368177491374
2022	50.041323650159